This invention relates to a process for the conversion of echinocandin class of peptides of the formula I 
wherein W, X, Y, Z, R and Rxe2x80x2 are as defined herein below:
to their C4-homotyrosine monodeoxy analogues of the formula I wherein W, Y, Z, R and Rxe2x80x2 are as defined herein below:
particularly to a process for the conversion of mulundocandin (compound of the formula II) 
to deoxymulundocandin (compound of the formula III) 
1,3-xcex2-glucan synthesis inhibitors are effective antifungal agents Candida albicans and also Pneumocystis carini, an opportunistic organism responsible for an often fatal pneumonitis among HIV patients and other immunocompromised hosts. Of all the structural classes of 1,3-xcex2-glucan synthesis inhibitors, only the echinocandins received considerable attention [Ref: J. Med. Chem. 35, 198-200 (1992)]. Echinocandin class of peptides are cyclic hexapeptides having a lipophilic side chain.
Several methods for the conversion of echinocandins to the corresponding deoxy analogues under acidic conditions have been reported [Ref: Tetrahedron Letts., 33, 4529-4532 (1992); U.S. patent application Ser. No. 222,157 dated Apr. 4, 1994]. The above methods involve selective reduction of C4-htyr (homotyrosine) hydroxyl group of echinocandins to their monodeoxy analogues with prior protection/deprotection of the equally facile C5-Orn (ornithine) hydroxyl group.
Mulundocandin [J.Antibiotics, 40, 275-280 and 281-289 (1987)] and deoxymulundocandin [Indian patent No. IN I69830 ; J.Antibiotics. 45, 618-623 (1992)] having antifungal properties were isolated from Aspergillus sydowii (Bainier and Sartory) Thom and Church var. Nov. Mulundensis Roy (culture no.HIL Y-30462). Deoxymulundocandin was found to possess better antifungal activity than mulundocandin. However, the production of deoxymulundocandin during the fermentation was 200 times less than that of mulundocandin.
We have found out by extensive research and experimentation that echinocandin class of peptides of the formula I may be converted to the corresponding C4-htyr monodeoxy analogues, particularly mulundocandin to deoxymulundocandin under neutral conditions. Accordingly, the object of the present invention is to provide a process for the conversion of echinocandin class of peptides of the formula I to the corresponding C4-homotyrosin monodeoxy analogues, particularly mulundocandin (compound of formula II) to deoxymulundocandin (compound of formula III).
According to the invention, there is provided a process for the conversion of echinocandin class of peptides of the formula I 
wherein W, X, Y, Z, R and Rxe2x80x2 are as defined herein below:
to the C4-homotyrosine monodeoxy analogues of the formula I, wherein W, X, Y, Z, R and Rxe2x80x2 are as defined herein below:
particularly to a Process for the conversion of Mulundocandin (compound of the formula II 
to deoxymulundocandin (compound of the formula III) 
which consists of a single step selective reduction of C4-htyr (homotyrosine) hydroxyl group of echinocandins to their monodeoxy analogues particularly under neutral conditions without prior protection, deprotection of the equally facile C5-Orn (ornithe) hydroxyl group and purification of the monodeoxy compound from the crude reaction mixture.